Understanding the genetic mechanisms that promote lineage commitment and eliminate autoreactive thymocytes in the thymus has direct relation to human disease. My research involves identifying new molecules important in the development and differentiation of the thymus, and characterizing their molecular basis in regulating immune responses to both self and non-self. Studying and understanding self-tolerance mechanisms may result in therapeutic treatments for patients with harmful autoimmune diseases. [unreadable] My experimental design involves the identification and characterization of novel molecules necessary for proper cell development and differentiation. I use genomics (Serial Analysis of Gene Expression) to [unreadable] identify specific gene products differentially expressed in distinct T cell populations. I then characterize the molecules with a novel RNAi method to generate gene-specific deficient mice. In brief, lentivirus containing gene specific shRNA is introduced into purified hematopoetic stem cells (HSC's). RAG2 -/- recipient mice are then reconstituted with HSC's to generate gene-specific knockdown mice. [unreadable] With these combined genomic and RNAi-based methodologies I identified and characterized MINK [unreadable] (Misshapen-NIK-related kinase), which is important for negative selection in the thymus. Further, I aim to extend the use of these approaches to characterize other molecules identified by SAGE. [unreadable] This research will contribute to identifying new molecules important for immune responses and [unreadable] self-tolerance. Moreover, the rapid characterization of their biological functions will help to understand and find the proper targets for treating autoimmune diseases. [unreadable] [unreadable] [unreadable] [unreadable]